Investigations into chromosomes 1, 2 and 3 of Coelopa frigida (Fab.)

Abstract

In Coelopa frigida 3 out of the 5 long chromosomes show inversion polymorphism. Detailed maps of salivary gland chromosomes 1, 2 and 3 were constructed. All the inversions found in the throe chromosomes are paracentric. Chromosome2, and 3, carried the simple single inversions, whereas Chromosome 1, carries throe overlapping inversions. The standard sequence adapted for Chromosome 2 and 3 had to be chosen arbitrarily. Of the two sequences (a) and (b) of Chromosome 1 sequence (a) has to be regarded as the original one because of the pattern of overlapping inversions. Puffing patterns of selected loci wore investigated under physiologically normal and abnormal, conditions mainly in 3rd instare larvae, pupae, and adults. Five loci on chromosome 3R were studied during 24 stages of development. Seven loci on Chromosomes1 and 2 only during five stages. 3R puffs at 17B and 17C show continuous puffing activity 17D1-3 and 17D4-6 intermittent activity, and puff 18A is restricted to the time after spiracle eversion. From the observation obtained of studying the puff locus 18A in the salivary gland and malpighian tubules in the same animal, after the spiracle eversion, it was found that this puff is of tissue-specific, showing activity only in the salivary gland chromosomes. Of the five loci studied in 1R, loci 1A to 2A shows continuous puffing activity. Loci 3B, 5C(a) and 5C(b) are active in the late 3rd instare, but regress after spiracle eversion. The two 2nd Chromosome loci 11A and 13A, are active after spiracle eversion. Immersion of 136 hour larvae in sea water (to which the larvae are normally exposed), as well as in 50% sea water, tap water, and distilled water produced a variable pattern. In general all these solutions were found to induce puffing activity after different periods of exposure except puff loci 17B, and 17C of continuous puffing activity, which they show no reaction, Puff loci 3B, 5C(a) and 5C(b)regress after 8 - 16 hours exposure to the different solutions, then recover at longer periods of treatment.